الفهرس 
Introductionيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The aim of this work is to study the pedicle screw fixation as regards anatomy, biomechanics of the pedicle, technique of fixation and different indications of the pedicle screw fixation then studying the different and the main factors affecting the pedicle screw fixation. The pedicle offers the strongest point of the vertebra. It composed of a cortical shell and cancellous core with certain proportion, also it has an external dimensions ”height, width, length” and di fferent angulation at different levels and internal dimensions. The thoracic pedicle is different from that of the lumbar spine because its mediolateral diameter is significantly less than its superio inferior diameter and it has less medial inclination. The dural sac lies immediately medial to the pedicle, and the spinal nerve roots run superior and inferior to the pedicle as they exit from the dural sac. Also, determination of the pedicle length help in determination of the proper screw length. Pedicle screw fixation is considered a short segment fixation which achieve stabilization of an abnormal level as the pedicle represents the strongest point of attachment to the spine, significant forces can be applied to the spine without failure of the bone-metal junction. Pedicle screw fixation systems are superior to the anterior fixation systems, in restoring and maintaining spinal alignment. Because they traverse all three columns of the spine also, they provide a longer lever arm through which the longitudinal member (rod or plate) can transmit greater corrective forces than are achieved with spinal fixation systems that.